This invention relates generally to method and apparatus for insertion of a foldable lens or optic through a narrow width incision in the eye; and into the corneo-scleral limbus of the eye, more particularly it concerns formation and use of a foldable lens having light occluding, de-bulked portions or segments to facilitate such insertion.
Recent efforts to achieve clear vision by use of a lens implant have led to use of a hard plastic lens of narrowed width to be passed through an incision or wound (of about 7 mm length) in the eye surface. However, visual distortion can then result, because external light rays can then pass through the pupil extents not covered by the reduced dimension lens implant, during de-centering of the lens implant in the eye.
Visual distortion and "glare" become increasingly disabling with either enlargement of the pupil, or decentration of the lens implant, both of these being possible under extreme conditions. Decentration occurs when the lens implant is improperly placed in the eye, or adhesions draw the implant out of centered condition. Further, the pupil can be dilated excessively due to medication or stimulation such as created by fear or excitement, or in a dark environment.
There is, accordingly, need for a means to alleviate the problem of such visual distortion, as well as need for improvements in soft lenses that will avoid the visual distortion problem as well as aid insertion of such lenses, as through narrowed incisions. There is also need for a distortion alleviating provision of an opaque zone on the lens, especially when de-bulking of the optic is present, and especially under decentration conditions.